Connected: An Internet Encyclopedia
RFC 1334 - 2.2. Packet Format

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Up: 2. Password Authentication Protocol
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Next: 2.2.1. Authenticate-Request

### 2.2. Packet Format

Exactly one Password Authentication Protocol packet is encapsulated in the Information field of a PPP Data Link Layer frame where the protocol field indicates type hex c023 (Password Authentication Protocol). A summary of the PAP packet format is shown below. The fields are transmitted from left to right.

        0                   1                   2                   3
        0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |     Code      |  Identifier   |            Length             |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |    Data ...
       +-+-+-+-+

Code

  The Code field is one octet and identifies the type of PAP packet. PAP Codes are assigned as follows:

               1       Authenticate-Request
               2       Authenticate-Ack
               3       Authenticate-Nak

Identifier

  The Identifier field is one octet and aids in matching requests and replies.

Length

  The Length field is two octets and indicates the length of the PAP packet including the Code, Identifier, Length and Data fields. Octets outside the range of the Length field should be treated as Data Link Layer padding and should be ignored on reception.

Data

  The Data field is zero or more octets. The format of the Data field is determined by the Code field.

2.2.1. Authenticate-Request
2.2.2. Authenticate-Ack and Authenticate-Nak

Next: 2.2.1. Authenticate-Request

Connected: An Internet Encyclopedia
RFC 1334 - 2.2. Packet Format